Molecular Biology Commons^™

Escherichia Coli Lacking Rpos Are Rare In Natural Populations Of Non-Pathogens, Emily Snyder '11, David M. Gordon, Daniel M. Stoebel

All HMC Faculty Publications and Research

The alternative sigma factor RpoS controls a large regulon that allows E. coli to respond to a variety of stresses. Mutations in rpoS can increase rates of nutrient acquisition at the cost of a decrease in stress resistance. These kinds of mutations evolve rapidly under certain laboratory conditions where nutrient acquisition is especially challenging. The frequency of strains lacking RpoS in natural populations of E. coli is less clear. Such strains have been found at frequencies over 20% in some collections of wild isolates. However, laboratory handling can select for RpoS-null strains and may have affected some of these strain …

The Role Of Ess1 In Survival, Morphogenetic Switching And Transcription In The Fungal Pathogen Candida Albicans, Dhanushki Poornima Samaranayake

Legacy Theses & Dissertations (2009 - 2024)

Candida albicans is a fungal pathogen that causes serious infections among immune-compromised patients and premature infants. C. albicans can become drug resistant, therefore, identifying new antifungal drug targets is an important goal. Here, we study a peptidyl-prolyl cis/trans isomerase called Ess1 as a potential drug target. Ess1 is conserved among pathogenic fungi, and therefore, potential inhibitors of Ess1 should display a broad spectrum of activity. We confirm that Ess1 is essential for growth in Candida albicans, but unlike the previously published find, deleting one copy of the C. albicans ESS1 gene did not affect morphogenetic switching. However, further reducing activity …

Gld-1 Represses Its Puf Mrna Targets Prior To/At Initiation Of Translation In The C.Elegans Germline, Gautham Sarathy

Legacy Theses & Dissertations (2009 - 2024)

The C.elegans germline offers an ideal system to study posttranscriptional regulation of gene expression as it is a major mechanism through which the control over gene expression is achieved. GLD-1 (defective in GermLine Development) is a maxi-KH motif containing RNA binding protein that controls various aspects of germline development from decision over germcell proliferation vs. meiotic entry to the production of mature gametes suggesting that GLD-1 likely controls many mRNA targets.

Investigation Of A 16s Rna Central Domain Pseudoknot, Jenna Marie Jasinski-Bolak

Wayne State University Theses

X-ray crystallography of the prokaryotic 30S ribosomal subunit revealed a myriad of complex RNA-RNA, RNA-protein, and protein-protein interactions. Among these are several phylogenetically conserved RNA pseudoknots. Pseudoknots are structurally and functionally diverse RNA secondary structures. They are generally formed by two short complimentary sequences separated by many bases of single stranded regions or loops. These relatively simple folds are often yield complex structures that are key components of functionally important conformational changes in RNA structure. One such pseudoknot is located in the central domain of the 16S rRNA.

The central domain pseudoknot is formed by Watson-Crick base pairing between G570-C866 …

Prevalence And Physiological Significance Of Gene Looping In Saccharomyces Cerevisiae, Banupriya Mukundan

Wayne State University Dissertations

My Ph.D. dissertation work is focused on studying the role of promoter-bound transcription initiation factors involved in gene looping. In this study we showed that the RNAP II subunit Rpb4 has a significant effect on termination of transcription. Gene looping is disrupted in the absence of Rpb4. Rpb4 shows a strong physical interaction with the Mediator subunit Srb5. Mediator subunit Srb5 crosslinked to the 5' and 3' ends of INO1 and CHA1 genes and is required for proper termination of transcription of these genes. Srb5 affected termination of transcription through its interaction with the CF1 complex. Srb5 interaction with the …

A Proposal To Test The Effects Of Factor Ecat1 On Pluripotency, From Reprogramming To Differentiation Of Human Somatic Cells, Vritti R. Goel

CMC Senior Theses

The field of stem cell research has been growing more because of the interest in using stem cells to cure diseases and heal injuries. Human embryonic stem cells, because of the controversy surrounding them—and subsequently the difficulties in acquiring samples of the existing aging cell lines—can only be used in limited capacities. While the development of induced pluripotent stem cells in the last decade has allowed the field to progress closer to medical treatments, the low efficiency of reprogramming a somatic cell to a pluripotent state, and the vast molecular and genomic differences between human embryonic stem cells and human …

The Role Of Receptor Tyrosine Kinase Axl In Pancreatic Ductal Adenocarcinoma And Its Regulation By Hematopoietic Progenitor Kinase 1, Xianzhou Song

Dissertations and Theses (Open Access)

Pancreatic ductal adenocarcinoma (PDA) is one of the most aggressive malignancies with less than 5% of five year survival rate. New molecular markers and new therapeutic targets are urgently needed for patients with PDA. Oncogenic receptor tyrosine kinase Axl has been reported to be overexpressed in many types of human malignancies, including diffuse glioma, melanoma, osteosarcoma, and carcinomas of lung, colon, prostate, breast, ovary, esophagus, stomach, and kidney. However, the expression and functions of Axl in PDA are unclear. We hypothesized that Axl contributes to the development and progression of PDA. We examined Axl expression in 54 human PDA samples …

Investigating The Roles Of Ndj1 And Tid1 In Crossover Assurance In Saccharomyces Cerevisiae, Rianna Knowles

Master's Theses

Meiosis is the specialized process of cell division utilized during gametogenesis in all sexually reproducing eukaryotes, which consists of one round of DNA replication followed by two rounds of chromosome segregation and results in four haploid cells. Crossovers between homologous chromosomes promote proper alignment and segregation of chromosomes during meiosis.

Crossover interference is a genetic phenomenon in which crossovers are non-randomly placed along chromosomes. Crossover assurance ensures that every homologous chromosome pair obtains at least one crossover during Prophase I. Crossovers physically connect homologous pairs, allowing spindle fibers to attach and separate homologs properly. However, some organisms have shown an …

Electrosensory Ampullary Organs Are Derived From Lateral Line Placodes In Bony Fishes, Melissa S. Modrell, William E. Benis, R. Glenn Northcutt, Marcus C. Davis, Clare V.H. Baker

Faculty Articles

Electroreception is an ancient subdivision of the lateral line sensory system, found in all major vertebrate groups (though lost in frogs, amniotes and most ray-finned fishes). Electroreception is mediated by 'hair cells' in ampullary organs, distributed in fields flanking lines of mechanosensory hair cell-containing neuromasts that detect local water movement. Neuromasts, and afferent neurons for both neuromasts and ampullary organs, develop from lateral line placodes. Although ampullary organs in the axolotl (a representative of the lobe-finned clade of bony fishes) are lateral line placode-derived, non-placodal origins have been proposed for electroreceptors in other taxa. Here we show morphological and molecular …

Expression Of Hyp-O-Glycan Modified Protein In Plant Using Transient And Cell Culture Platforms, Di Wu

Student Theses and Dissertations

Plants have emerged as cost-effective, efficient factories to produce foreign proteins of pharmaceutical importance. Agrobacterium-mediated transient expression provides a rapid and simple plant system for production but is often linked with low protein recovery. Plant-specific hydroxyproline (Hyp)-O-glycosylation has been demonstrated to increase protein stability and solubility (termed Hyp-Glyco technology). To test if Hyp-glycans attached to a target protein can improve overall transiently expressed protein yields, EGFP reporter protein was expressed as fusion with a 5 or 32 repeats of Ser-Pro motif ((SP)5 or (SP)32 ) that directs extensive Hyp-O-glycosylation. My thesis project has provided the first demonstration that the Hyp-O-glcosylation …

Interspecies Comparison Of Αii-Spectrin Abundance Between Chinook Salmon And Steelhead, Brielle D. Kemis, Ann L. Miracle, Katie A. Wagner, Christa M. Woodley

STAR Program Research Presentations

Salmonids, such as Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss), are a staple economic, recreational, tribal, and environmental resource, yet many populations are unsustainable. This study was part of a broad scale effort to monitor the impact of downstream migration obstacles on juvenile salmonid health and survival, which is an essential step towards increasing Smolt-to-Adult Return ratios (SARs). The objective of this study was to determine if juvenile Chinook salmon and steelhead exhibit differing quantities of alphaII-Spectrin Breakdown Products (SBDPs) over two consecutive spring migration periods, indicative of neurogenesis rate and/or biological response to head …

Significance Of Increased Tissue Transglutaminase In Hormone Refractory Prostate Cancer, Amy L. Han

Dissertations and Theses (Open Access)

The progression of hormone responsive to hormone refractory prostate cancer poses a major clinical challenge in the successful treatment of prostate cancer. The hormone refractory prostate cancer cells exhibit resistance not only to castrate levels of testosterone, but also to other therapeutic modalities and hence become lethal. Currently, there is no effective treatment available for managing this cancer. These observations underscore the urgency to investigate mechanism(s) that contribute to the progression of hormone-responsive to hormone-refractory prostate cancer and to target them for improved clinical outcomes.

Tissue transglutaminase (TG2) is a multifunctional pro-inflammatory protein involved in diverse physiological processes such as …

Mechanism Of Transcriptional Suppression Of A Phytochrome A Epiallele In Arabidopsis Thaliana, Gulab D. Rangani

Graduate Theses and Dissertations

Cytosine methylation in DNA is an integral part of epigenetically controlled regulatory networks in eukaryotes. Both plants and vertebrates display DNA methylation in the gene coding region; however, its role in gene expression is not well understood. Gene promoter, on the other hand, remains largely unmethylated. Acquisition of methylation in promoter results in transcriptional suppression of the gene. The goal of this research is to study the effect of coding region methylation in gene expression using a unique gene model, phyA'. phyA' is a transcriptionally suppressed epiallele of the Arabidopsis thaliana Phytochrome A gene, which contains methylation in CG sites …

Downregulation Of Pax2 Suppresses Ovarian Cancer Cell Growth, Huijuan Song

Dissertations and Theses (Open Access)

PAX2 is one of nine PAX genes regulating tissue development and cellular differentiation in embryos. PAX2 promotes cell proliferation, oncogenic transformation, cell-lineage specification, migration, and survival. Unattenuated PAX2 has been found in several cancer types. We therefore sought to elucidate the role of PAX2 in ovarian carcinomas. We found that PAX2 was expressed in low-grade serous, clear cell, endometrioid and mucinous cell ovarian carcinomas, which are relatively chemoresistant compared to high grade serous ovarian carcinomas. Four ovarian cancer cell lines, RMUGL (mucinous), TOV21G (clear cell), MDAH-2774 (endometrioid) and IGROV1 (endometrioid), which express high-levels of PAX2, were used to study the …

Dissecting The Interaction Between P53 And Trim24, Aundrietta D. Duncan

Dissertations and Theses (Open Access)

Dissecting the Interaction of p53 and TRIM24

Aundrietta DeVan Duncan

Supervisory Professor, Michelle Barton, Ph.D.

p53, the “guardian of the genome”, plays an important role in multiple biological processes including cell cycle, angiogenesis, DNA repair and apoptosis. Because it is mutated in over 50% of cancers, p53 has been widely studied in established cancer cell lines. However, little is known about the function of p53 in a normal cell. We focused on characterizing p53 in normal cells and during differentiation. Our lab recently identified a novel binding partner of p53, Tripartite Motif 24 protein (TRIM24). TRIM24 is a member of …

Sunday Driver/Jip3 Binds Kinesin Heavy Chain Directly And Enhances Its Motility, Faneng Sun, Chuanmei Zhu, Ram Dixit, Valeria Cavalli

Biology Faculty Research

Neuronal development, function and repair critically depend on axonal transport of vesicles and protein complexes, which is mediated in part by the molecular motor kinesin‐1. Adaptor proteins recruit kinesin‐1 to vesicles via direct association with kinesin heavy chain (KHC), the force‐generating component, or via the accessory light chain (KLC). Binding of adaptors to the motor is believed to engage the motor for microtubule‐based transport. We report that the adaptor protein Sunday Driver (syd, also known as JIP3 or JSAP1) interacts directly with KHC, in addition to and independently of its known interaction with KLC. Using an in vitro motility assay, …

Role Of The Mar-Sox-Rob Regulon In Regulating Outer Membrane Porin Expression, Lon Chubiz, Christopher Rao

Biology Department Faculty Works

Multiple factors control the expression of the outer membrane porins OmpF and OmpC in Escherichia coli. In this work, we investigated the role of the mar-sox-rob regulon in regulating outer membrane porin expression in response to salicylate. We provide both genetic and physiological evidence that MarA and Rob can independently activate micF transcription in response to salicylate, leading to reduced OmpF expression. MarA was also found to repress OmpF expression through a MicF-independent pathway. In the case of OmpC, we found that its transcription was moderately increased in response to salicylate. However, this increase was independent of MarA and Rob. …

Molecular Evolution And Historical Biogeography Of New World Birds, Brian T. Smith

UNLV Theses, Dissertations, Professional Papers, and Capstones

Deciphering the patterns of how biodiversity has evolved across time and space has remained a fundamental objective for biologists for the last 200 years. Researchers are faced with the challenge of interpreting the complexity of evolutionary patterns that have been generated over the deep history of the Earth. The advancement of DNA sequencing technology has yielded a new and powerful genetic toolkit that has allowed biologists to address novel evolutionary questions. For my dissertation research, I used molecular genetics and a statistical framework to study the evolution and historical biogeography of birds distributed in North and South America. My dissertation …

Section Abstracts: Biology With Microbiology And Molecular Biology

Virginia Journal of Science

Abstracts of the Biology with Microbiology and Molecular Biology Section for the 89th Annual Meeting of the Virginia Academy of Science, May 25-27, 2011, University of Richmond, Richmond VA.

Acute Synaptic Activity Causes Differential Mirna Expression In The Drosophila Melanogaster Larval Central Nervous System, Robert Ian Sand

Electronic Theses and Dissertations

The primary goal of this thesis was to determine if spaced synaptic stimulation induced the differential expression of microRNAs (miRNAs) in the Drosophila melanogaster central nervous system (CNS). Prior to attaining this goal, we needed to identify and validate a spaced stimulation paradigm that could induce the formation of new synaptic growth at a model synapse, the larval neuromuscular junction (NMJ). Both Channelrhodopsin- and high potassium-based stimulation paradigms adapted from (Ataman, et al. 2008) were tested. Once validation of these paradigms was complete, we sought to characterize the miRNA expression profile of the larval CNS by miRNA array. Following attainment …

Identification And Characterization Of Equine Rotaviruses In Southern Ireland, Crystal Cronin

Theses

Group A Rotaviruses(GARVs) are enteric pathogens which induce acute gastroenteritis in infants, neonates and the young of many animal species. During a 4 year study (2005-2009), 64 fecal samples from symptomatic foals, from several counties, in the south of Ireland, were molecularly characterized to determine the VP& (G type), VP4 (P type), and NSP4 antigenic specificities. Globally, G3 [P12] and G14[P12] are recognized as the predominant equine GARV strains. Twenty-two samples (34.38%) were found to contain G3 viruses, while 21 samples (32.81%) contained G14 viruses. In this study, there was a distinct increase in the incidence of mixed infections circulating …

Molecular, Cellular And Systemic Effects Of Atrazine On The Xenopus Laevis Tadpole, Renee Maryanne Zaya

Dissertations

Atrazine is one of the two most commonly used herbicides in the US and it is the most studies are among the first to link physiological effects of atrazine to changes in tissue and gene expression in Xenopus laevis tadpoles. These studies provide the groundwork for future studies into the mechanisms behind responses to chemical stressors generating data resulting in a better understanding of how these chemicals affect us all. commonly found herbicide in ground water. As a result, a great deal of attention has been placed on its use and safety. It has also been implicated to play a …

Design And Application Of Composite Rna Aptamers, Shengchun Wang

Legacy Theses & Dissertations (2009 - 2024)

aptamers are being developed as an essential tool in many fields of biological research. Their utility is not limited to being protein inhibitors; a lot of novel functions can be realized. However, in vivo application of RNA aptamers still faces many challenges. The aim of this dissertation is to design and apply composite aptamers in multiple expression and delivery systems to address some critical issues, such as correct folding, high level production, degradation by nucleases, excessive consumption of cellular resource and potential toxic effect.

Rox1 Function In Dosage Compensation: Structural / Functional Analysis Of A Non-Coding Rna, Ying Kong

Wayne State University Dissertations

roX1 is a long non-coding RNA involved in the chromosome-wide gene regulation that occurs during dosage compensation in Drosophila. Dosage compensation in Drosophila melanogaster occurs by a global two-fold increase of transcription from the single male X chromosome. This essential process compensates for X chromosome monosomy. The male-specific lethal (MSL) complex, containing five proteins, localizes to the male X chromosome and alters chromatin to modify gene expression. roX1 and roX2 RNAs are redundant components of MSL complex that are required for its exclusive X-localization. Recent studies in our lab have revealed a second role of roX RNAs in heterochromatic gene …

Quantifying Agonist Activity At G Protein-Coupled Receptors, Frederick J. Ehlert, Hinako Suga, Michael T. Griffin

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

When an agonist activates a population of G protein-coupled receptors (GPCRs), it elicits a signaling pathway that culminates in the response of the cell or tissue. This process can be analyzed at the level of a single receptor, a population of receptors, or a downstream response. Here we describe how to analyze the downstream response to obtain an estimate of the agonist affinity constant for the active state of single receptors.

Receptors behave as quantal switches that alternate between active and inactive states (Figure 1). The active state interacts with specific G proteins or other signaling partners. In the absence …

Intraspecific Variation In Two Cosmopolitan Myxomycetes, Didymium Squamulosum And Didymium Difforme (Physarales: Didymiaceae), Katherine Elizabeth Winsett

Graduate Theses and Dissertations

The myxomycetes (plasmodial slime molds or myxogastrids) are one of three groups considered to be true slime molds (class Eumycetozoa sensu Olive 1975). Two vegetative states--amoebae and plasmodia--along with a spore-producing fruiting body characterize the life cycle of the myxomycetes. These organisms are associated with decaying plant material and are found in all terrestrial habitats worldwide. A number of species are considered cosmopolitan, being found worldwide, where they are associated with a diversity of microhabitats and substrates. A review of the literature, including molecular investigations in all three groups of slime molds, is presented, and this is followed by four …

Excision Dynamics Of Vibrio Pathogenicity Island-2 From Vibrio Cholerae: Role Of A Recombination Directionality Factor Vefa, Salvador Almagro-Moreno, Michael G. Napolitano, E. Fidelma Boyd

Dartmouth Scholarship

Vibrio Pathogenicity Island-2 (VPI-2) is a 57 kb region present in choleragenic V. cholerae isolates that is required for growth on sialic acid as a sole carbon source. V. cholerae non-O1/O139 pathogenic strains also contain VPI-2, which in addition to sialic acid catabolism genes also encodes a type 3 secretion system in these strains. VPI-2 integrates into chromosome 1 at a tRNA-serine site and encodes an integrase intV2 (VC1758) that belongs to the tyrosine recombinase family. ntV2 is required for VPI-2 excision from chromosome 1, which occurs at very low levels, and formation of a non-replicative circular intermediate.

Aromatic Acid Metabolites Of Escherichia Coli K-12 Can Induce The Marrab Operon, Lon Chubiz, Christopher Rao

Biology Department Faculty Works

MarR is a key regulator of the marRAB operon involved in antibiotic resistance and solvent stress tolerance in Escherichia coli. We show that two metabolic intermediates, 2,3-dihydroxybenzoate and anthranilate, involved in enterobactin and tryptophan biosynthesis, respectively, can activate marRAB transcription. We also found that a third intermediate involved in ubiquinone biosynthesis, 4-hydroxybenzoate, activates marRAB transcription in the absence of TolC. Of the three, however, only 2,3-dihydroxybenzoate directly binds MarR and affects its activity.

Rna Processing Of Nitrogenase Transcripts In The Cyanobacterium Anabaena Variabilis, Justin Ungerer, Brenda Pratte, Teresa Thiel

Biology Department Faculty Works

Little is known about the regulation of nitrogenase genes in cyanobacteria. Transcription of the nifH1 and vnfH genes, encoding dinitrogenase reductases for the heterocyst-specific Mo-nitrogenase and the alternative V-nitrogenase, respectively, was studied by using a lacZ reporter. Despite evidence for a transcription start site just upstream of nifH1 and vnfH, promoter fragments that included these start sites did not drive the transcription of lacZ and, for nifH1, did not drive the expression of nifHDK1. Further analysis using larger regions upstream of nifH1 indicated that a promoter within nifU1 and a promoter upstream of nifB1 both contributed to expression of nifHDK1, …

A New Tumor Suppressor Gene Candidate Regulated By The Non-Coding Rna Pca3 In Human Prostate Cancer, Alessandro K. Lee

Dissertations and Theses (Open Access)

Prostate cancer is the second leading cause of cancer-related death and the most common non-skin cancer in men in the USA. Considerable advancements in the practice of medicine have allowed a significant improvement in the diagnosis and treatment of this disease and, in recent years, both incidence and mortality rates have been slightly declining. However, it is still estimated that 1 man in 6 will be diagnosed with prostate cancer during his lifetime, and 1 man in 35 will die of the disease.

In order to identify novel strategies and effective therapeutic approaches in the fight against prostate cancer, it …